Introduction

In some web projects I had to implement a configuration user interface containing a file selecting action. For the first time, I did a simple
ASPX page, but soon after I needed it in another ASPX page and I found a the user control would be a better solution. Furthermore it
was a good opportunity to develop an interesting web custom control and apply it in an application.

Background

User controls are an easy kind of custom controls. They can be created as simply as creating an ASP.NET web page, using the Visual Studio
Toolbox for designing and the code behind for defining properties and methods for the control. They can be then included in your ASP.NET
web pages, using only the public members for input/output operations. All internal actions are encapsulated in the control and are not visible
from the outside. You can't damage the - in some cases - very complex layout, which you designed with several hours of troublesome work. You
can define other properties, e.g., to change the background or the forecolor properties of the control.

Using the code

The user control has been designed as an Explorer-like file browser, allowing the setting of access credentials, the start
(root) directory, and finally selecting a file for any custom action. It consists, for the most part, a TreeView control for browsing
directories and a ListView control for browsing files. The layout of the user control is determined by a CSS file.